First run sensors to see which sensors chips you have, for example:

-8<-
% sensors
k10temp-pci-00c3
Adapter: PCI adapter
temp1:       +57.0°C

atk0110-acpi-0
Adapter: ACPI interface
Vcore Voltage:      +1.36 V  (min =  +0.85 V, max =  +1.60 V)
 +3.3 Voltage:      +3.26 V  (min =  +3.00 V, max =  +3.60 V)
 +5.0 Voltage:      +4.89 V  (min =  +4.50 V, max =  +5.50 V)
+12.0 Voltage:     +12.16 V  (min = +11.20 V, max = +13.20 V)
CPU FAN Speed:     4166 RPM  (min =    0 RPM)
CHASSIS FAN Speed: 1086 RPM  (min =    0 RPM)
CHASSIS2 FAN Speed: 710 RPM  (min =    0 RPM)
POWER FAN Speed:      0 RPM  (min =    0 RPM)
CPU Temperature:    +59.0°C  (high = +90.0°C, crit = +125.0°C)
MB Temperature:     +40.0°C  (high = +45.0°C, crit = +90.0°C)
-8<-

The chip name is above the adapter name as the first of the three words
separated by a dash. The second and third words are busname and address.

My computer has two sensors, the temperature sensor in my AMD processor
named "k10temp" and another sensor on my Asus mainboard named "atk0110".

By default wmgtemp just selects the first usable sensor chip, therefore
I need to force wmgtemp to use the atk0110 chip:

-8<-
% wmgtemp -c atk0110
wmgtemp: Primary Sensor - atk0110 on ACPI interface
-8<-
or
-8<-
% wmgtemp --chip=atk0110
wmgtemp: Primary Sensor - atk0110 on ACPI interface
-8<-

If the chip selection option is omitted, wmgtemp selects the first
sensor chip:

-8<-
% wmgtemp               
wmgtemp: Primary Sensor - k10temp on PCI adapter
-8<-