ABB Symphony Harmony Series, Instruction, Page: 137 / 402

3 - 8 WBPEEUI240751C0
I/O Block
I/O modules can be removed and installed while system power
is applied. With the I/O module removed, current mode analog
input channels are maintained if configured to use local field
power (refer to
Block Power
Block Power Block Power
Block Power in this section). Voltage mode ana-
log input channels, however, and analog output, digital input,
and digital output channels are in an open circuit state in a
nonredundant configuration. I/O channels will continue to
operate normally when one of the modules in a redundant con-
figuration is removed.
Figure 3-7 is a block diagram of the I/O circuitry. The block
diagram generally reflects the operation of all I/O blocks. The
I/O section varies from block to block.
Block Power
Each block provides onboard regulation for any operating volt-
ages it requires. The I/O module accepts redundant 24 VDC
inputs which it filters, auctioneers, and regulates to produce
Figure 3-6. Configuration Jumper Access
T 01 60 3 A
AC C ES S
C OV ER
I/O BO AR D
R E TR AC TA BLE
H A N D LE