Siemens SIMATIC S7-1200

Technical specifications
A.3 Fail-Safe signal module (SM) technical specifications
S7-1200 Functional Safety Manual
Manual, 02/2015, A5E03470344-AA
187
Model
SM 1226 F-DQ 2 x Relay
Off delay time Typically 16 ms to first series contact open, second contact
opens approximately 40 ms later.
Behavior on RUN to STOP Only 0 (OFF) is allowed.
Number of outputs on simultaneously
2
Parallel connection of 2 outputs Allowed for redundant availability. Do not exceed single relay
load rating.
Control of a digital input
With 24 VDC SELV supply
Switching frequency:
• With resistive load
• With inductive load in accordance with IEC 60947-5-1,
DC13
• With inductive load in accordance with IEC 60947-5-1,
AC15
• Inductive load in accordance with UL 508
2 Hz, maximum
0.1 Hz, maximum
2 Hz, maximum
Pilot Duty B300, R300
Cable length (meters)
• 200 m shielded
• 200 m unshielded
Reverse polarity protection
No
A.3.4.4
Relay output circuits
The SM 1226 F DQ 2 x Relay has two output channels (F-DQ a.0 and F-DQ a.1). Each
channel includes two circuits that switch mechanically-linked contacts at the same time.
Each circuit has two contacts in series controlled by independent relay coils. Opening and
closing of the series contacts in each circuit is sequenced to avoid common wear-out
failures.
Output channel a.0: Two circuits controlled as one process output channel
Refer to the isolation description in the SM 1226 F-DQ 2 x Relay (Page 185) specifications, Digital
outputs table.