APC Back-UPS ES 500 with Synology NAS

The NAS is a Synology DS411+II. The UPS is an APC Back-UPS ES 500 connected to the NAS with the supplied USB cable.
With the UPS connected to the NAS, go to the NAS’ web page (port 5000). From the top left menu button, select “System Information”. On the General tab, under External Devices, you should see the UPS. From there, go to Control Panel, select Power, select the UPS tab and select Enable UPS support.

The following instructions are based on the Synology forum post “Success with DS-209 and APCupsd UPS Monitoring“. Although the NAS can see the UPS and gets status from it, I was unable to get apcupsd to work.

To install the monitoring deamon, log in to the NAS as root:
ipkg install apcupsd
Edit the file /opt/etc/apcupsd/apcupsd.conf.
If you have more than one UPS, set the UPSNAME to keep them straight. This is optional. Change UPSCABLE to usb. Change UPSTYPE to usb and set DEVICE to blank.
mkdir -p /opt/var/lock
mkdir -p /opt/var/log
touch /opt/var/log/apcupsd.events
touch /opt/var/log/apcupsd.status

To test: apcupsd -b -d5 -T -f /opt/etc/apcupsd/apcupsd.conf. Open another shell to the NAS ans root and run apctest.