Field Notes Bulletin - SIGA-CR Modules Connected to MR

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Field Notes Bulletin - TECHNICAL SUPPORT FNN 10021 • I S S 07SEP10
Signature: SIGA-CR Modules Connected to MR Series Multivoltage Control Relays

Introduction
This bulletin informs you of an issue with SIGA-CR modules connected to MR Series Multivoltage Control Relays, and tells you how to resolve it.

Issue
Due to a change by Air Products, the 120 VAC input circuits on MR-100, -200, and -800 Series Multivoltage Control Relays present a capacitive load to the SIGA-CR, instead of a resistive load. As a result, the SIGA-CR contacts do not reliably change state when activated, even though the red “Active” LED turns on and it activates a relay confirmation event. SIGA-CR activation is not affected when using the 24 V input control voltages on the control relay. Figure 1 on page 2 shows the difference between new board layouts (with capacitors) and old board layouts (without capacitors). We are attempting to find out when Air Products changed their product design. Until then, use Figure 1 on page 2 to determine if this change affects you. Note: Other Signature modules that have contacts rated for 120 VAC at 500 mA, Pilot Duty (inductive or resistive loads only) may also be affected. Typically, the SIGA-CR module is used in this type of application. In addition, other control relays such as the PAM-1 may be affected.