TRM1033 Analog Output: Calculating SSR Load Capacity

Tom Garrett1 min read
Motor ControlOther ManufacturerTechnical Reference
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That limit supports no more than 5 mA at 10 V. Three solid-state relay inputs drawing 2.5 mA each would require 7.5 mA and therefore exceed the documented load condition.

Calculate the Analog Output Load

Apply Ohm's law at the stated 10 V maximum: I = V / R. With the minimum permitted load resistance, Imax = 10 V / 2,000 ohm = 5 mA. An SSR input drawing 2.5 mA at 10 V presents an effective resistance of R = 10 V / 0.0025 A = 4 kOhm.

Parallel SSR inputs Total input current at 10 V Equivalent resistance Result
One 2.5 mA 4 kOhm Within the stated limit
Two 5 mA 2 kOhm Exactly at the stated limit
Three 7.5 mA Approximately 1.33 kOhm Below the 2 kOhm minimum; unsupported

Do Not Combine Output Capacity by Assumption

The available evidence does not state that leaving the second output unused increases the current capacity of the first output. Treat the 2 kOhm minimum as the limit for the selected analog output unless the manufacturer confirms another arrangement. To operate three SSR inputs, use an interface that presents at least 2 kOhm to the controller and provides the required downstream current, subject to manufacturer confirmation of compatibility.

Assess Relay-Started Fan Operation Separately

Before finalizing the circuit, document the intended fan command, actuator operation, single-stage heater command, required interlocks, and shutdown sequence. Submit that sequence and the proposed wiring to OWEN through[email protected] for confirmation; the available response requests these project details but does not approve the proposed topology.

FAQ

How much current can the TRM1033 0-10 V output supply?

From the stated minimum load of 2 kOhm, the calculated current limit at 10 V is 5 mA.

Can one TRM1033 analog output drive three 2.5 mA SSR inputs?

No supported conclusion permits it. Three parallel inputs draw 7.5 mA and present approximately 1.33 kOhm, which violates the stated minimum load of 2 kOhm.

Can the TRM1033 start the supply fan by relay without a VFD?

The supplied evidence does not confirm that configuration. Provide the proposed command sequence, wiring, and safety interlocks to OWEN support for product-specific approval.

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