User`s guide

14
34980A general-purpose
switch modules
The 34980A general-purpose switches can
be used to route signals or to control other
system devices. These switches are ideal
for device actuation and switching loads or
power supplies.
Choose from the following features:
• FormCchannelsupto1A,50W
• FormAchannelsupto5A,150W
• Armaturelatchingrelays
• Simultaneouschannelswitching
• Temperaturesensortodetect
overheating conditions
• Connectionsviastandard50or78-pin
Dsub cables or detachable terminal block
The34937Aisthemostversatilegeneral-
purpose switch with 28 Form C channels that
can switch up to 1 A of current. In addition,
this module has four Form A channels that
can switch up to 5 A of current. For power
switching applications, the 34938A has 20
5-amp channels in a Form A topology. Each
Form A general-purpose switch can handle
up to 150 W, enough for many power line-
switching applications. For high density
applications the 34939A offers 64 Form A
channels for switching up to 1A and carry
currents up to 2A.
The general purpose switches contain
latching armature relays where multiple
channels can be closed at the same time.
Additionally, for switching reactive loads,
the optional terminal blocks have pads for
snubbing circuits.
The built-in relay counter helps predict
when relays need to be replaced.
Table 5. GP actuator selection table—specifications and characteristics
34937A 34938A 34939A
Channels/configurations 28 Form C 20 Form A 64 Form A
4 Form A
Switch type Armature, latching Armature, latching Armature, latching
Input characteristics (per channel)
Maxvolts(DC,ACRMS)
[1]
 FormC–300V 30VDC/250VAC +/-100Vpeak
 FormA–30VDC/250VAC
Maxcurrent(DC,ACRMS) FormC–1A(2Acarry) 5Aswitch 1Aswitch
 FormA–5Aswitch (8Acarry) (2Acarry)
(8 A carry)
Power (W, VA)
[2]
 FormC–60W  60W
 FormA–150W 150W
Volt-Hertz limit 10
8
10
8
10
8
General specifications
Offset voltage 3 uV 3 uV 3 uV
Initialclosedchannelres FormC–125mΩ  <125mΩ
 FormA–50mΩ <60mΩ
DCIsolation(ch-ch,ch-earth) >10GΩ >10GΩ 10GΩ
AC characteristics
Bandwidthatterminalblock[3] 10MHz 1MHz 10MHz
Channel Isolation at terminal block [3]
100kHz 55dB 60dB 45dB
1MHz 35dB 40dB 25dB
10MHz 15dB  5dB
Capacitance at terminal block
CH–CH FormC12pF/FormA10pF 65pF 20pF
CH–earth FormC21pF/FormA18pF 105pF 70pF
General characteristics
Relaylifenoload/rated FormC–100M/100k  >100M/100k
 FormA–50M/30k 50M/30k
Open/closetime FormC–4ms/4ms 10ms/10ms 4ms/4ms
 FormA–10ms/10ms
Initial/resetrelaystate FormC–maintainstate userconfigurable maintain
 FormA–userconfigurable
Analogbusbackplaneconnection No No No
[1] DCorACRMSvoltage,channel-to-channelorchannel-to-earth
[2] Limitedto6Wofchannelresistancepowerlosspermodule
[3] 50Ωsource,50Ωload,differentialmeasurementsverified(S21)
Channel 001
(1A form C relay)
NC
NO
COM
Channel 028
(1A form C relay)
NC
NO
COM
Channel 029
(5A form A relay)
NO
COM
Channel 032
(5A form A relay)
NO
COM
Figure 9. 34937A 32-channel Form A/
Form C switch