Zebra ZT411 S7-1500 Integration: TIA V16 TCP/IP Label Printing

Overview

This technical reference covers the complete integration of a Zebra ZT411 industrial label printer (model ZT41142-T4E0000Z) with a Siemens SIMATIC S7-1500 CPU programmed in TIA Portal V16. The link between the PLC and the printer is built on standard TCP/IP socket communication (Open User Communication, OUC), which the S7-1500 supports natively without any additional CP or software.

The integration solves four concrete engineering problems reported in the field:

1. Triggering a print job from the PLC (cycle start, button on HMI, completion signal of a machine step).
2. Embedding dynamic data into the printed label (part number, batch ID, date, time, operator).
3. Receiving the printer status back into the PLC (online/offline, error, ribbon out, head open).
4. Reading the printer clock or supplying date/time when the ZT411 internal RTC drifts.

The driver stack in the ZT411 is Zebra's PrintServer II / ZebraNet which exposes a raw TCP socket on port 9100 (default). Any ASCII string sent to this socket that conforms to ZPL II is executed as a print job. No proprietary Siemens block is required; only the standard OUC instructions TCON, TDISCON, TSEND_C and TRCV_C from the TIA Portal basic instructions library.

System Architecture and Prerequisites

Hardware List

Software Prerequisites

• TIA Portal V16 (with HSP 0263 or later if using a recent CPU).
• S7-1500 CPU firmware V2.6 or newer loaded on the target PLC.
• Optional: ZebraDesigner 3 or Zebra Setup Utilities for offline label layout generation and ZPL string export.
• ZPL II Programming Guide (Volume I and II) from Zebra for command reference.

IP Addressing Plan

Use a private subnet dedicated to the printer network. A typical layout:

Zebra ZT411 Network Configuration

1. Power on the ZT411 and open the front LCD panel.
2. Navigate to Menu → Networks → Wired IP.
3. Set the IP address to 192.168.0.8, subnet mask 255.255.255.0, gateway 192.168.0.1.
4. Navigate to Menu → Networks → Print Server → Port 9100 and confirm the raw socket is enabled.
5. Set the active print language to ZPL via Menu → Settings → Print Language (do not leave it on hybrid).
6. Print a configuration label: hold the Feed key while powering on, or use Menu → Settings → Print Info. Confirm the IP is shown on the test label.
7. Ping the printer from a Windows command prompt: ping 192.168.0.8. A successful reply confirms the Ethernet stack.

Detailed firmware and driver downloads for the ZT411 family are available on the Zebra ZT411 support and downloads page.

TIA Portal V16 Project Configuration

Adding the S7-1500 Station

Open TIA Portal V16 and create a new project. Add a SIMATIC S7-1500 station that matches the physical CPU. Open the device configuration, set the PROFINET interface X1 IP address to 192.168.0.3 with subnet 255.255.255.0. Compile and download the hardware configuration.

Adding the Printer to the Network Topology (Optional)

Strictly speaking the ZT411 is not added to the device configuration as a slave because it is not a PROFINET device; it is a pure TCP/IP terminal on the same subnet. However, TIA Portal V16 allows you to drop an unspecified Ethernet node on the network view for documentation purposes. The OUC connection is configured entirely in the user program, not in the hardware configuration.

Adding the Connection DB

Insert a new global DB called dbZebraConnection. It must contain a TCON_IP_V4 structure (system data type). The minimum fields to populate:

Reference the system constants for the local PROFINET interface ID via System constants → <CPU> → Local Interface → Local PROFINET interface.

Adding the Print String DB

Create a second global DB called dbPrintstring with a STRING[1024] tag called Printstring plus separate STRING tags for each dynamic field (sPartNumber, sBatchID, sDate, sTime, sOperator). The maximum ZPL II script length for a single label is well below 1024 bytes; the S7-1500 string type has a max length of 254 characters per default STRING, so size it to STRING[1024] or use an ARRAY OF BYTE for safety.

PLC Program: Connection, Send and Receive Blocks

Block Selection

For a single TCP partner the combined instruction TSEND_C and TRCV_C is the cleanest approach because they handle the TCON / TDISCON state machine internally. The legacy TCON + TSEND + TRCV triplet is recommended only when you need fine-grained control over connection lifecycle (e.g., scheduled re-establishment after a line stop).

Pattern: Single FB fbZebraPrint

Place the OUC blocks in an SCL Function Block. The following pattern covers print trigger, status request, and reset of the connection.

// SCL - fbZebraPrint instance DB
REGION Connection and I/O
  // TSEND_C: send a ZPL script on demand
  #tsendPrinter(
    REQ       := #i_bPrintTrigger AND #bPrinterOnline,
    CONT      := TRUE,
    LEN       := INT_TO_UINT(LEN(#dbPrintstring.Printstring)),
    CONNECT   := "dbZebraConnection".TCON_IP_V4,
    DATA      := #dbPrintstring.Printstring,
    COM_RST   := #bComReset,
    DONE      => #bSendDone,
    BUSY      => #bSendBusy,
    ERROR     => #bSendError,
    STATUS    => #wSendStatus);

  // TRCV_C: receive the printer response (ZPL status / ~HS answer)
  #trcvPrinter(
    EN_R       := TRUE,
    CONT       := TRUE,
    LEN        := 0,                   // 0 = take all data received
    CONNECT    := "dbZebraConnection".TCON_IP_V4,
    DATA       := #stRecvBuffer,
    COM_RST    := #bComReset,
    VALID      => #bRecvValid,
    BUSY       => #bRecvBusy,
    ERROR      => #bRecvError,
    STATUS     => #wRecvStatus,
    LEN        => #iRecvLen);
END_REGION

ZPL II Command Reference for the ZT411

The ZT411 interprets Zebra Programming Language II (ZPL II). A complete label is a single ASCII stream terminated by ^XZ. The minimum useful print job looks like:

^XA
^FO50,50^A0N,40,40^FDHello ZT411^FS
^XZ

The command structure is ^<letter> for format commands, ~<letter> for immediate-action commands, and ^FD<data>^FS for field data delimited by ^FS. Below are the commands used most often on the S7-1500 line.

Printer Status Request (~HS)

To read the printer state, send only ~HS as a one-byte-per-line job:

~HS

The ZT411 replies with a multi-line ASCII block on the same TCP socket. Typical response:

PRINTER STATUS
ERRORS:
WARNING:
IDLE

Other valid values inside the response are PRINT HEAD OPEN, MEDIA OUT, RIBBON OUT, PAUSE, HEAD TOO HOT, HEAD COLD. Parse this string in the PLC to drive an HMI status display.

Embedding the Printer Clock

ZPL II can insert the printer's internal RTC into a field. The format is set by ^CF / ^CT:

^XA
^FO50,50^A0N,30,30^FDDate: ^FSD ^FS
^FO50,90^A0N,30,30^FDTime: ^FST ^FS
^XZ

Where ^FSD writes the configured date format and ^FST writes the configured time format. Configure both via ^CDF:YYYY-MM-DD and ^CTF:HH:MM:SS.

Building Dynamic Print Strings in SCL

The original Siemens example uses VAL_STRG to convert integers to formatted strings. A cleaner, locale-independent approach is to use the DTL to STRING conversion plus concatenation of ZPL fragments.

Sample FB: fbBuildPrintstring

// SCL - build a ZPL II label with PLC-side date/time
FUNCTION_BLOCK "fbBuildPrintstring"
VAR
  #i_dtLocalTime : DTL;        // connect to CPU RD_SYS_T (returns DTL)
END_VAR
BEGIN
  // ZPL header
  #dbPrintstring.Printstring := '';
  Concat := CONCAT(IN1 := #dbPrintstring.Printstring,
                   IN2 := '^XA^FO50,50^A0N,40,40^FDPN: ');
  Concat := CONCAT(IN1 := Concat, IN2 := #sPartNumber);
  Concat := CONCAT(IN1 := Concat, IN2 := '^FS');

  // Date line, formatted in PLC
  Concat := CONCAT(IN1 := Concat,
                   IN2 := '^FO50,110^A0N,30,30^FDDate: ');
  Concat := CONCAT(IN1 := Concat, IN2 := DTL_TO_STRING(#i_dtLocalTime));
  Concat := CONCAT(IN1 := Concat, IN2 := '^FS');

  // Code 128 with serial number from PLC tag
  Concat := CONCAT(IN1 := Concat,
                   IN2 := '^FO50,170^BY3^BCN,80,Y,N');
  Concat := CONCAT(IN1 := Concat, IN2 := '^FD');
  Concat := CONCAT(IN1 := Concat, IN2 := #sSerialNumber);
  Concat := CONCAT(IN1 := Concat, IN2 := '^FS');

  // End of label / print trigger
  Concat := CONCAT(IN1 := Concat, IN2 := '^XZ');
  #dbPrintstring.Printstring := Concat;
END_FUNCTION_BLOCK

If DTL_TO_STRING yields the locale-dependent form 2026-01-15-13:45:22, strip the dashes and colons with REPLACE if you want a flat format such as 20260115 134522.

Manual Integer-to-String Formatting (matches the field-tested example)

// Day as two-digit decimal
VAL_STRG(IN  := UINT_TO_INT(#i_dtLocalTime.DAY),
         SIZE := 2,
         PREC := 0,
         WIDTH := 0,
         P    := 1,
         OUT  => #sDay);
#dbPrintstring.Printstring[LEN := ...].dateField := #sDay;

The VAL_STRG instruction pads with leading blanks if WIDTH is 0; set WIDTH > 0 to pad with leading zeros on positive values.

Status Polling and Parsing

The ZT411 closes the TCP socket after each command. The PLC must handle this gracefully; TSEND_C / TRCV_C do this automatically because CONT := TRUE keeps the connection state alive across sends.

Recommended Polling Cycle

1. Every 2 seconds, send ~HS as a separate OUC job on the same connection.
2. Wait for VALID := TRUE on TRCV_C.
3. Search the receive buffer for the keywords PRINTER STATUS, IDLE, PAUSE, HEAD OPEN, MEDIA OUT, RIBBON OUT.
4. Drive Boolean tags (bPrinterReady, bPrinterError, bHeadOpen) based on the keyword matches.
5. Display the raw buffer on HMI for diagnostics.

Receive Buffer Sizing

The ZT411 ~HS response is under 200 bytes. A STRING[512] receive buffer is sufficient. Avoid LEN := 0 on TRCV_C if you want a hard cap; set LEN := 512 to fix the maximum block size and prevent buffer overruns if the printer firmware produces a larger response.

Complete Working Cycle (Step-by-Step)

1. Compile and download the hardware configuration. Confirm 192.168.0.3 is reachable from the engineering station.
2. Configure the ZT411 as described above; print a config label and verify IP.
3. Ping both directions: ping 192.168.0.8 from the engineering station, then trigger a one-shot TSEND_C from the PLC with a known string (e.g. ~HS) and confirm DONE := TRUE with status word 16#0001 within one cycle.
4. Enable the connection DB in Properties → Connection → Active connection establishment on PLC side if you are using TCON directly. With TSEND_C, this is implicit.
5. Load the FB block fbZebraPrint and the fbBuildPrintstring into the S7-1500 CPU.
6. Trigger a print from the PLC by setting i_bPrintTrigger := TRUE for one cycle, or use an HMI button wired to the same tag. The label should advance through the printer within 1-2 seconds.
7. Verify date/time on the printed label. If blank or wrong, check whether you used ^FSD (depends on printer clock) or a literal ^FD<string>^FS (depends on PLC tag).
8. Force a fault (open the print head) and confirm the next ~HS poll returns the HEAD OPEN string. This validates the receive path.

Verification Checklist

Troubleshooting Matrix

Performance Notes

• Round-trip time for a single ~HS poll: typically 50-100 ms on a 100 Mbit subnet.
• Print cycle of a 4-inch by 2-inch label at 203 dpi: ~1 s after the ZPL stream is fully sent.
• Maximum ZPL stream throughput: the 9100 socket on the ZT411 does not flow-control well above ~50 KB/s; for very large labels (>20 KB ZPL) split the job or buffer the receive side with a 200 ms TSEND_C spacing.
• PLC program OB1 cycle overhead for one TSEND_C + one TRCV_C: ~0.5 ms; well within the budget of any S7-1500 CPU.

Safety and Operational Notes

Reference Architecture Diagram

FAQ