GE Industrial Solutions Entellisys System User Manual - Manual (Page 131)

Discrete inputs/outputs 131
10
10.1.1.5 Relays
Entellisys uses two types of relays: input and output. Both are optically isolated, solid state
relays. Recommended relays are 70G-IDC5 and 70G-IAC5 for inputs and 70G-ODC5R for
outputs. 70G-IDC5 is DC driven relay and it can accept from 3 to 32 Vdc of input voltage. The
other input relay, 70G-IAC5 is an AC driven relay and it can accept from 90 to 140 Vac of input
voltage. All of the relays are manufactured by Grayhill. Input relays support negative logic, such
as when a relay is closed or on, the LED indicator is “ON”, but the signal that it feeds discrete
input is low, and vice versa. To make sure that LED “ON” corresponds to the “ON” state in the
CPUs' logic, they reverse or negate the input states. Output relays can accept 100 Vdc or
120 Vac with logic voltage ranging from 4.8 to 6 Volts.
NOTE: If an input relay is “ON” and voltage measurement is taken on the control side of the
relay, low voltage is indicated on the measuring device. The voltage is high when the relay is
“OFF”.
For more detailed information about the relays or if any other type of relays is used, please see
the manufacturer's specifications.
10.1.1.6 Relay blocks
Relays are screwed to a relay block. Each relay block can accept up to 16 relays. Different relay
types (inputs vs. outputs) cannot be mixed on the same relay block. These restrictions, along
with number of inputs and outputs in the system, determine how many relay blocks are
necessary. The recommended relay block for use with inputs and outputs is 70GRCK16I-DIN
from Grayhill. This is a DIN rail-mounted version that allows for greater installation flexibility. For
more details about the relay block, please refer to manufacturer's specification.